The primary objectives of the proposed two studies are to ascertain the: a) interrelationships between sensorimotor functions and masticatory performance, food selection and patient satisfaction in dentate persons and denture wearers; and b) influence of an EMG biofeedback program to establish a chewing pattern of similar bilateral muscle activity in denture wearers and the effects of this change on their masticatory performance, food selection, and patient satisfaction. In Study 1, 140 denture patients with clinically acceptable dentures will be divided into two equal groups of low and high masticatory performance. A control group of 70 dentate persons with 28 or more teeth will provide the reference values and estimates of variability for assessing alterations of sensory, motor and perceptual functions, masticatory performance and other measures. Medical and dental histories, clinical orofacial and denture evaluations and subjective ratings of food preference and satisfaction will be collected. Objective measures of masticatory performance, masseter EMG activity, bite force, tactile and two-point discrimination thresholds, stereognostic ability, salivary secretion rates and oral clearance ability will be made. The comparisons between dentate subjects and denture wearers with high and low performance will be made to assess any alterations in oral sensory, motor and perceptual functions in denture wearers and their impact on masticatory performance, patient satisfaction and food selection. In Study II, the effects of an EMG biofeedback program, to produce a bilateral pattern of chewing effort on masticatory efficiency will be evaluated in 90 denture wearers with low masticatory performance. Patients will be randomized into a control group of 45 or an experimental biofeedback group of 45 persons. Bilateral masseter EMG activity will be recorded while the patients perform bite force and preferred side and swallowing threshold masticatory tests with peanuts. The experimental group will then participate in bi-weekly EMG biofeedback sessions for eight weeks. The biofeedback program will be designed to alter the chewing pattern so that patients learn to apply equal masseter muscle activity bilaterally. The control group will follow the same schedule of bi-weekly sessions for eight weeks. They will be given instructions to chew bilaterally and will not receive the biofeedback. The performance tests and subjective evaluations will be repeated after four weeks of training, at the end of the eight week training period and thereafter at three months.